call us toll free:


​Washington On-Site Sewage Association

Top News


1515 Commerce Street
Tacoma, Washington 98402
(253) 591.9100 


1320 Broadway 

Tacoma, WA 98402

(253) 238-8000

As a WOSSA Member, be sure to vote and elect your choice of candidates to the 2020 WOSSA Board. Please follow the link below to vote for your favorite candidates. If you are not currently a member you can join or renew.

It is with great sadness that we inform you of the passing of Dean Bannister. 

He passed away November 6, 2019. Dean was a valued member of Washington's onsite industry for many years and will be missed. Please keep Dean’s family in your thoughts as they go through this difficult time.

2020 WOSSA Board Election

For over 20 years WOSSA's goal has been to promote professional excellence through education, advocacy...

Whether you’re an employer or someone looking to get hired on, having the skills, attitude and knowledge...


Calendar of Events

In a deliberate effort to raise awareness and reduce workplace injuries related to

Pathogen Exposure, Confined Space Entry, OSHA Construction Focus Four: Falls, Caught-in or between, Struck by and Electrocution

WOSSA has developed new training resources that focus on workers in the On-Site industry. This training delivers both knowledge and practical skills to address the numerous hazards that are unique to our industry.

These videos were developed by WOSSA as an integral part of these safety training classes.


It is always a challenge to find a quality service provider within any trade...

Washington On-Site Sewage Association MembershipRecently, Jerry Stonebridge, John Thomas...

WOSSA Membership

Voice of the INDUSTRY

"Voice of the Industry" for Members, Consumers, Our Communities & the Environment"

Washington State has approximately 1.5 million decentralized wastewater systems in use, it is our mission as an Association, with the help of our members, consumers and local government; to ensure that we put the water back into our communities the way we found it. Helping to replenish nature’s support system with a long term sustainable approach to wastewater disposal and treatment.